This invention relates to a projectile construction and more particularly to arrows or spears and arrowheads or spearheads with automatically staged, sequential functions.
Archery, once practiced for survival, is a growing recreational sport. Limited projectile range is a significant consideration in suburban area woods where long range firearms may involve safety hazards. Likewise, it is this same limited range which makes the taking of a game animal more of a challenge to the sportsman, due not only to the necessity of finding an animal, but also of having to get within close range. Resultant low bow-hunter success rates allow longer archery hunting seasons while maintaining reasonable wildlife harvests. These longer seasons have been one of the main contributing factors in archery's growing popularity. Undermining the above theory, though, is the relative inefficiency of archery projectiles of the prior art.
Arrows generally move at velocities, and with kinetic energies, greatly inferior to those of firearm projectiles, and are incapable of transmitting significant shock to internal organs. Immediate internal hemorrhage is limited, and progressive bleeding is the primary cause of fatality. Arrowheads of broad configuration, designed for maximum internal cutting, usually encounter excessive resistance in hide, external musculature, or skeleton, being either deflected from complete entry or being deformed and dulled prior to reaching the target's vital interior. Narrower heads of efficient penetrating design may pass completely through game; however, these heads cut internal wound channels of less than optimal size. Such wounds may quickly close, cause bleeding too slow to be fatal, or so slow that the sportsman may not be able to retrieve his quarry in a reasonable time, if at all. The result is that many animals are maimed, crippled, or wounded in a marginal manner, dying a slow death, and are largely unharvested. Often these dead or incapacitated animals are not reported to conservation authorities and upset the long-season computations, thereby thwarting positive game management.
In recognition of the above operative effects, a large amount of research into arrowhead improvement has been conducted. Prior art has described many compromises in fixed bladed arrowheads, where penetration and cutting ability were balanced by varying widths, angles of attack, number of blades, and curvature of cutting blades. The different mechanics of penetration of a relatively dense target exterior, and those of efficient and extensive cutting of the target interior, preclude optimal function in both particulars by a single fixed blade system.
A further improvement in the dual functions of penetration and cutting was effected by the introduction of pivotal, or moveable bladed arrowheads, where a head of efficient penetrating design acted as a chassis for moveable cutting blades. Proposals ranged from simple arrangements of free, sometimes partly exposed cutting blades, to intricate, locked, fully shrouding devices. While the locked, fully shrouding devices moved towards the optimum in both required separate functions, they also introduced unreliability due to reality of manufacturing tolerances and susceptibility to impact damage and malfunction. Additionally, fabrication costs could be excessive. The simpler, unlocked and/or exposed mechanisms tended to have less efficiency of one or the other function, or exhibited problems of premature deployment and malfunction.
Another, unrelated advancement came in the advent of pneumothorax inducing shafts, which are shafts which facilitate the introduction of air into a chest cavity to induce mortality by pulmonary collapse. Conventional combination of this advancement with prior art fixed bladed heads exhibited problems of fixed bladed arrows in either failure to penetrate or rapid arrow exit from the target. Combinations with prior art moveable bladed heads introduced less than optimal efficiency or unreliability. Additionally, imprecise arrow location in the target due to premature deployment, malfunction, or collapse of the expanded head and subsequent shifting, dictated that pneumothorax inducing shafts contain holes along their entire length. Such multiplicity of holes often causes whistling during flight which prematurely alerts game and causes misses.
The present invention sets about to solve problems in the prior state of the art by utilizing the separated function advantages of moveable-bladed arrows. The invention is able to take advantage of the locked, shrouded arrangement's ability to avoid premature deployment and maximize penetration efficiency, while avoiding fragile, intricate arrangements, and the unreliability inherent in a large number of moving parts. The invention's arrangement is able to incorporate modifications to provide novel functions which further the potential of the art. Specifically, the invention's moveable-bladed arrowhead may be made brushproof; that is, its triggering mechanism may be made safe from premature deployment while passing through vegetation. Additionally, a novel triggering device to simultaneously deploy the cutting blades at a preferred depth after target penetration, may be provided. Also, a number of options are provided which are able to restrain the deployed cutting arrangement from collapsing so it may continue to effect its design function. Further, by means of efficient, reliable expansion of the head, a device is provided to accurately and reliably position and, when desirable, retain a hollow, pneumothorax inducing shaft. This accurate positioning allows a pneumothorax inducing shaft to be used which contains only a single aperture at its end, thereby avoiding whistling or noise problems and also insuring optimal pneumothorax inducing function.
In sum, the present invention incorporates the most desirable potentials of the art into a versatile coordinated whole, which reliably provides a precise, automatic, sequential phasing and positioning of a number of components for optimal independent function.
Incidental to the development process, designs were produced for a penetrating head or tip portion which significantly reduces friction during penetration, thereby maximizing residual kinetic energy. This greater residual energy greatly enhances positive reliability of actuation and function in the target's vital interior.